This is documentation for an old release of NumPy (version 1.15). Read this page Search for this page in the documentation of the latest stable release (version 2.2).

numpy.diagflat

numpy.diagflat(v, k=0)

Create a two-dimensional array with the flattened input as a diagonal.

Parameters:

v : array_like

Input data, which is flattened and set as the k-th diagonal of the output.

k : int, optional

Diagonal to set; 0, the default, corresponds to the “main” diagonal, a positive (negative) k giving the number of the diagonal above (below) the main.

Returns:

out : ndarray

The 2-D output array.

See also

diag

MATLAB work-alike for 1-D and 2-D arrays.

diagonal

Return specified diagonals.

trace

Sum along diagonals.

Examples

>>>

>>> np.diagflat([[1,2], [3,4]])
array([[1, 0, 0, 0],
       [0, 2, 0, 0],
       [0, 0, 3, 0],
       [0, 0, 0, 4]])

>>>

>>> np.diagflat([1,2], 1)
array([[0, 1, 0],
       [0, 0, 2],
       [0, 0, 0]])